WSP04463

• File Number: 8460.500
• Description: Platte River Recovery Plan
• Basin: South Platte
• Date: 6/1/1997
• Author: Colo Div of Wildlife
• Title: Inventory and Status of South Platte River Native Fishes in Colorado
• Water Supply Pro - Doc Type: Publication

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INTRODUCTION

The streams and rivers of the Front Range and eastern plains of Colorado have received
little attention as fishery resources in the past due to their higWy fluctuating and turbid nature,
characteristics that did not promote or sustain recreational fishery attributes. Even among those
streams that are perennial, low base flows were not conducive to supporting traditional
warmwater fisheries common in the eastern and mid-western United States. Warmwater, riverine
habitats within eastern Colorado are dominated by native .fish species that have little sport fishery
potential. Management of aquatic wildlife in these streams has been minor in scope. These
habitats will accommodate introduced, lentic game fish species only when they have been
significantly modified via impoundment. A primary value of these stream habitats is the
maintenance of native fish assemblages, including a number of potentially threatened, endangered,
and special concern fish species. Despite a general lack of conservation management in the past,
native fish species persist in these Front Range and eastern plains streams.

Unlike mountain streams, few perennial tributaries supplement the main channel flows of
the South Platte River Basin in the eastern plains. Increasing demands are being placed by human
development on the state's water resources, including surface and groundwater depletions,
diversions, impoundments, and degradation of water quality. Public concern has also increased
over the welfare of aquatic wildlife species dependent upon these dwindling or higWy modified
stream flows. Thirty-one native fish species historically inhabited waters of the South ~Iatte River
Basin. Currently, 28 native and 44 nonnative species may be found in the basin. Within the native
fishes group, the greenback cutthroat trout, Oncorhynchus clarki stomias, is federally listed as
threatened and is now found only in headwaters of the basin. Two species, the hornyhead chub,
Nocomis biguttatus, and blacknose shiner, Notropis heterolepis, are extirpated. It is believed the
sauger, Stizostedion canadense, was also an early inhabitant of the mainstem river but is also
extirpated. The plains minnow, Hybognathus placitus, represented in a 1978-1980 inventory by
the collection of one specimen, was characterized as an "occasional resident" by Propst (1982).
Nine species are currently considered species of special concern due to their rare or declining
status.

In 1991-1992, the Colorado Division of Wildlife (CDOW) began planning for a broad
scope inventory of all streams in the Front Range and eastern plains portions of the South Platte
River Basin in Colorado. During the field seasons of 1992 through 1994, inventory data on fish
species, habitat and water quality was collected. The most immediate need of the CDOW was to
evaluate the relative "health" of these warmwater stream communities via the distribution, relative
abundance, and status of native fish species; the presence of habitat to sustain these species (flow,
water quality, and channel bed characteristics); and the nature of possible effects from interaction
with nonnative fish species. The community-level management goal was to characterize biotic
diversity in the South Platte River and identifY native fish species communities and their habitats.